topic 3: redox I

Question 1

what is oxidation

Answer 1

electron loss

Question 2

what is reduction

Answer 2

electron gain

Question 3

what is the rules for assigning oxidation numbers

Answer 3

1. all uncombined elements have an oxidation number of zero
2. the oxidation numbers of the elements in a compound add
   up to zero
3. the oxidation number of a monoatomic ion is equal to the
   ionic charge
4. in a polyatomic ion (CO3
   2-) the sum of the individual
   oxidation numbers of the elements adds up to the charge
   on the ion
5. several elements have invariable oxidation numbers in their
   common compounds.
   Group 1 metals = +1
   Group 2 metals = +2
   Al = +3
   H = +1 (except in metal hydrides where it is –1 eg NaH)
   F = -1
   Cl, Br, I = –1 except in compounds with oxygen and fluorine
   O = -2 except in peroxides (H2O2 ) where it is –1 and in compounds with fluorine

Question 4

how can oxidation number of an element with various oxidation numbers be represented

Answer 4

roman numerals

Question 5

what is the reducing agent

Answer 5

electron donor

Question 6

what is the oxidising agent

Answer 6

electron acceptor

Question 7

what is the product when an acid and metal react

Answer 7

salt + hydrogen

Question 8

what is disproportionation

Answer 8

a reaction where the same species is oxidised and reduced simultaneously

Question 9

what is used to balance H atoms

Answer 9

H+

Question 10

what is used to balance out the O

Answer 10

H2O

Question 11

what is used to balance the oxidation number

Answer 11

electrons